#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define XH(i,a,b) for(int i = a; i < b; ++i)
#define XXH(i,b,a) for(int i = b; i >= a; --i)
#define Module 998244353
int tmpInt;ll tmpll;string tmpStr;char tmpChar;
vector<int>tmpIntVector;

int main(){
  int k;
  cin>>k;
  int i,j,x;
  ll ans = 0;
  for(i = 1; i <= k ; ++i){
    for( j = i; j<=k/i ; ++j){
      x = k/(i*j);
      if(x>=j){
        if(j==i){
          ans += 1;
          ans += 3*(x-j);
        }else{
          ans += 3;
          ans += 6 * (x - j);
//          cout<<i<<" "<<j<<" "<<x<<" "<<ans<<endl;
        }
      }
      else if(x == k){
        i = k;
        break;
      }
    }
  }
  cout<<ans<<endl;

  return 0;
}
